Oleg Belov, was wounded by police gunfire while resisting arrest and was in stable condition after undergoing surgery.

The dismembered remains of the children, all under the age of six, were discovered on Tuesday in the family's apartment in the city of Nizhny Novgorod, the federal Investigative Committee said. The body of his pregnant wife also was found there.

At a separate location, police found the remains of a woman believed to be his mother.

Belov was arrested in the Vladimir region, where he was hiding in his mother-in-law's home. Police suspect he planned to kill her, too.

A criminal case has been opened to determine whether police negligence had played a role in the deaths. Five officers are accused of ignoring repeated complaints from Belov's wife dating back to October that he was threatening to kill her and the children.